Field of the Disclosure
The present disclosure relates to an optical touch input device, and more particularly, to an optical touch input device which divisionally adjusts optical output of a light emitting unit before a touch operation and during the touch operation to reduce power consumption, and a driving method thereof.
Discussion of the Related Art
In general, a touchscreen is one of various devices which form an interface between information communication equipment using various displays and a user, and is an input device in which a user interfaces with equipment by directly contacting a screen using a hand or a pen.
The touchscreen is conversationally and intuitionally manipulated only through contact between a finger and a button displayed on a display and thus is easily used by people of all ages and both sexes, thus being recently applied to various fields, such as issuing machines in banks or public offices, various medical equipment, guide systems in tourist facilities and main government organizations, traffic guide systems, etc.
Such touchscreens are divided into a resistive type, a capacitive type, an ultrasonic wave type, an infrared type, etc., according to recognition methods employed.
Advantages of the above-described types are different, but an infrared type touchscreen minimizes pressure applied to a touch surface and has convenience in arrangement, thus recently attracting attention.
Infrared type touchscreens may be divided into an infrared matrix type, an infrared camera sensing type, etc., according arrangement structures of light emitting sources and light receiving sources and the numbers thereof.
A specific type may be preferred according to size of a display panel and whether or not it moves during assembly, and from among them, an infrared matrix type touchscreen includes a plurality of infrared light emitting sources and one image sensor.
However, in the case of the above-described infrared type touchscreen, the infrared light emitting sources continuously emit light even if touch input does not occur for a long time, and thus the infrared light emitting sources and the image sensor are operated even if touch does not actually occur, thus consuming unnecessary power. Thereby, the lifespan of the infrared light emitting sources is reduced due to unnecessary power consumption and thus causes a high power consumption rate.
Further, the lifespan of the infrared light emitting sources from among elements necessary for a display device is relatively shortened due to cyclic lighting of the infrared light emitting sources necessary for touch sensing, and thus accuracy in touch detection is lowered when the display device is used for a long time.
The above-described conventional infrared type touchscreen has problems, as follows.
The infrared light emitting sources continuously maintain the lighting state before or after touch driving, and unnecessary power is consumed even if touch does not occur or in a region in which touch does not occur.
Therefore, the lifespan of the infrared light emitting sources tends to be shortened due to increase in power consumption unnecessary during non-touch.